The field of the present invention is liquid dispensing assemblies, valves or taps and more particularly is directed to a dispensing assembly for use in drawing off liquid from the bottom of a container.
A typical container is a plastics molded bottle such as disclosed in U.S. Pat. No. 3,430,824. The container is typically made by a blow molded polyethylene process and comes in various shapes and sizes. Another well known container is known as a "bag within a box" where liquid is held in collapsible liner bag within a box. Typically these and other containers have an outlet neck located at the bottom of the container so that liquid may proceed by gravity flow into a receiving receptacle. Since the dispensing assembly is located at the bottom of the container, the assembly is constantly subjected to liquid pressure. The dispensing assembly must be leak proof and readily operable to dispense a desired quantity of liquid.
Heretofore there have been two primary dispensing valves. One such valve is the push-pull valve such as disclosed in U.S. Pat. No. 3,493,146. The push-pull valve includes a valve sleeve slidably mounted in a positioning sleeve, the valve sleeve having a opening therein which becomes exposed when the valve sleeve is pulled outward past the edge of the positioning sleeve thereby allowing fluid to flow out through the aperture.
Another dispensing valve is the diaphragm toggle-type such as disclosed in U.S. Pat. No. 3,400,866. The diaphragm toggle-type valve has a diaphragm wall which extends concavely into a spout opening contacting the inner edge of the spout thereby forming a closure or pressure seal therebetween. The valve is operated by manually actuating a toggle piece, distorting the wall, which allows fluid to pass between the diaphragm wall and the spout. Upon release of the toggle, the diaphragm returns to its original shape re-establishing the pressure seal.
Both the push-pull and the diaphragm toggle-type valves impart some sort of sliding, slipping, or lifting motion on the container in order to actuate the valve mechanism. The actuation motion required to operate the valve is often difficult. In addition, these devices require either a distortion or a sliding contact of the sealing surface which can reduce the seal effectiveness over use.